In the related art, for example, as disclosed in Japanese Unexamined Patent Application, First Publication No. 2013-46954 (A), a surface-coated cutting tool is known, in which a hard coating layer made of a complex carbonitride layer or a complex nitride layer that has an average thickness of 0.5 to 8.0 μm and satisfies a composition formula: (Al1-x-yCrxSiy)(N1-zCz) (where x, y and z satisfy 0.3≤x≤0.7, 0≤y≤0.1, and 0≤z≤0.3, respectively) is formed on the surface of a tool body; the hard coating layer includes particles containing 90 atomic % or more of metallic element with respect to constituent elements thereof; the particles have a cross-sectional long diameter of 0.05 to 1.0 μm and are dispersed at a longitudinal cross-sectional area ratio of 3 to 20% of the hard coating layer; 0.3≤A/(A+B) is satisfied where among the particles, A % is a longitudinal cross-section area ratio of particles of which the constituent elements contain 50 atomic % or more of Al and which has an aspect ratio of 2.0 or more in the longitudinal cross-section and the cross-sectional long diameter forming an acute angle of 45° or less with respect to the surface of the tool body and B % is a longitudinal cross-section area ratio of the other particles; and excellent fracturing resistance and wear resistance are exhibited in a face milling of a carbon steel, an alloy tool steel or the like.
As disclosed in Japanese Unexamined Patent Application, First Publication No. 2012-166333 (A), a surface-coated cutting tool is known, in which at least hard coating layer with a thickness of 0.5 to 10 μm and made of a complex nitride layer of Al and Cr is formed on the surface of a tool body; pores and droplets are dispersed in the complex nitride layer of Al and Cr; an area ratio occupied by the pores is 0.5 to 1 area % and an area ratio occupied by the droplets is 2 to 4 area % in an arbitrary cross-section of the complex nitride layer of Al and Cr; among the droplets, Al-rich droplets with Al content higher than the average Al content in the complex nitride layer of Al and Cr occupies an area of 20% or more with respect to the total area of the droplets in the arbitrary cross-section of the complex nitride layer of Al and Cr; and excellent fracturing resistance and wear resistance are exhibited in high-speed cutting of a carbon steel, an alloy tool steel or the like.
As disclosed in Japanese Unexamined Patent Application, First Publication No. 2008-238336 (A), a surface-coated cutting tool such as an end mill is known, in which a plurality of macro-particles protrude from the surface of a hard coating layer made of Ti1-a-bAlaMb(CxN1-x) (where M is one or more selected from group 4, 5, and 6 elements of Periodic table excluding Ti, rare earth elements, and Si, and a, b and x satisfy 0.40≤a≤0.65, 0≤b≤0.5, and 0≤x≤1, respectively); the macro-particles protrude from a rake face continuous with cutting edges of an end cutting edge and a peripheral cutting edge toward a direction away from the cutting edges at an average angle of 5 to 20° with respect to a normal direction to interface between a tool body and the coating layer; and the macro-particles incline and protrude thereby dispersing impact from chips, preventing the macro-particles from falling off, and improving chipping resistance.